Originally Posted by
kenn0223
On UA, for example, they 1) are very grumpy about adding back-up segments to a reservation to begin with and 2) an agent needs to resync the ticket coupons with the segments that will be used before you can board.
FWIW, that is not my experience on UA at all. I think both UA & DL are good, but I agree that the DL app is buggier sometimes when it comes to displaying itineraries in flux.
In the OP’s case, I hopefully would have a paper boarding pass and then just show up at the gate as if I had never looked at the app. A paper boarding pass here would be very valuable at the gate in the event of any issues.